A variational scheme for retrieving ice cloud properties from combined radar, lidar, and infrared radiometer
A variational scheme for retrieving ice cloud properties from combined radar, lidar, and infrared radiometer
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DOI：
10.1029/2007jd009000
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发表时间：
2008-04-09
影响因子：
4.4
通讯作者：
Hogan, Robin J.
中科院分区：
文献类型：
--
作者：
Delanoe, Julien;Hogan, Robin J.
介绍了一种利用地基或星载雷达、激光雷达和红外辐射计联合反演冰云可见光消光系数、冰水含量和有效半径廓线的变分方法。前向模型包括雷达的非瑞利散射和激光雷达的分子和多次散射等效应。通过严格的错误处理和仔细选择的状态变量和相关的先验估计，一个无缝的检索是可能的雷达和激光雷达检测到的云和区域之间的区域检测到这两个仪器之一。因此，当激光雷达信号不可用时（由于强衰减等原因），检索倾向于使用雷达反射率因子和温度的经验关系，当雷达信号不可用时（例如在光学薄卷云中），通过激光雷达和辐射计的组合仍然可以进行精确的检索。该方法进行了测试，首先从飞机数据的模拟配置文件，然后在西非采取的真实的意见。简单地通过包括其他测量的前向模型来扩展该方法以包括其他测量将是直截了当的。
A variational method is described for retrieving profiles of visible extinction coefficient, ice water content and effective radius in ice clouds using the combination of ground-based or spaceborne radar, lidar and infrared radiometer. The forward model includes effects such as non-Rayleigh scattering by the radar and molecular and multiple scattering by the lidar. By rigorous treatment of errors and a careful choice of state variables and associated a priori estimates, a seamless retrieval is possible between regions of the cloud detected by both radar and lidar and regions detected by just one of these two instruments. Thus, when the lidar signal is unavailable ( for reasons such as strong attenuation), the retrieval tends toward an empirical relationship using radar reflectivity factor and temperature, and when the radar signal is unavailable ( such as in optically thin cirrus), accurate retrievals are still possible from the combination of lidar and radiometer. The method is tested first on simulated profiles from aircraft data and then on real observations taken in West Africa. It would be straightforward to expand the approach to include other measurements simply by including a forward model for them.